Objective To study the effect of asymmetric inlet velocity profile on the wall shear stress of the position where atherosclerosis always happens.Methods Special software is used to construct the TF-AHCB model,set the asymmetric inlet velocity profile,and do the mesh dividing and the simulation work.The flow field of sinus and the distribution of wall shear stress on the different conditions of time and inlet velocity are calculated.The feature of flow field and shear stress which is related to the atherosclerosis is analyzed.Result Asymmetric inlet velocity profile deflexion could increase the area of low shear stress and the gradient of shear stress.Conclusion Asymmetric inlet velocity profile could be one of the dangerous factor to cause atherosclerosis.